Natural killer cells don’t clear HMPV

Human metapneumovirus (HMPV) is a major cause of serious respiratory disease in young children and the elderly. There is no vaccine currently available, and HMPV causes recurrent infections.

In explorations of the immune response to HMPV, Sherry Wen, an MSTP student and Ph.D. candidate, John Williams, M.D., and colleagues have examined the role of natural killer (NK) cells. NK cells are capable of killing infected cells and are critical to the innate immune response – the first line of defense against infection.

The researchers found that HMPV-infected mice had higher numbers of functional lung NK cells than mock-treated mice. To test whether these lung NK cells are required to clear HMPV, they depleted the NK cells. NK cell-depleted and control mice had no differences in HMPV virus levels, expression of cytokine factors, lung histopathology, and T cell numbers and function.

The findings, reported in the Journal of Virology, indicate that NK cells are not required to clear acute HMPV infections, and they further understanding of the pathophysiology associated with HMPV infection.